As a defensive driver our goal is to avoid an accident by avoiding common errors and save ourselves from mistakes of others. It requires observation skills to identify potential hazards and knowing how to avoid those by taking action on time.
Identify dangers before it happens :
Develop the ability to see potential dangers as they happen. For example,if the traffic on a highway is coming to a stop due to something, anticipate a rear end and be prepared to observe tailgaters closely and look for escape route.
Know what to do :
Each hazard requires a different response from us. Learn the response for each situation and try to apply it. For example,aquaplaning on a rainy day is a possible scenario. We should know what to do to avoid aquaplaning.
Take actions on time :
Never assume that the other driver will correct his mistake and brake on time to save us. Have enough crash avoidance space to allow you to take corrective actions on time.
Harold Smith the world famous driving instructor envisioned the Smith System of No Accident Driving in 1959 and it holds good even now.
Aim High in Steering:
Look far ahead while driving. Observe where your vehicle will be at least 15-20 seconds ahead on highways and in cities at least an intersection ahead. Look for hazards using your vision.
Get the Big Picture :
See more than what's in front of your eyes. Watch for potential hazards at every corner. Have a safe following distance to avoid your vision being blocked by vehicles ahead.
Keep Your Eyes Moving:
As traffic on the road is a continuously changing scene, we should also move our eyes every few seconds to scan for hazards and avoid motion Induced Blindness. Avoid fixing our eyes on an object for long.
Leave Yourself an Out :
Have enough crash avoidance space in case an emergency situation comes. Don't lock Yourself between traffic and get stuck.
Make Sure they see you :
Use your horn, lights, positioning of the vehicle by avoiding being in someone else's blindspot etc to let others know that you are there. By letting others know that you are there,you can avoid accidents.
A good video on the Smith System :